1. Field of the Invention
This invention relates to articulated vehicles and, more particularly, to linkages extending between at least two parts of the vehicle for controlling operating functions of the vehicle.
2. Description of the Prior Art
Articulated vehicles have been known and used for a long time so that the problems of transmitting control commands from an operator's station on a first frame to operate a functional piece of equipment on a pivotally attached second frame, are known. As a specific example on an articulated wheel loader, the operator's station is on a main frame with the engine, while the front wheels and bucket are on a loader frame pivotally attached to the main frame. The operator's commands are put into the control handles or pedals with some of the commands being transmitted to the loader frame by means of push-pull cables, electronic devices, or the like. Although these present day controls are effective and in widespread current use, they can occasionally have problems, such as fraying and breaking of the cables and malfunction of the electronics.
In certain vehicles, such as double articulated mining vehicles, the operator's station may be on an intermediate carriage with the engine and the like on a rear frame and with the bucket and the like on a front frame. Operator commands to the throttle, transmission or bucket must be transmitted to the front frame or rear frame across the articulated pivots such that the same degree of control must be transmitted no matter what the angular position of the frame is with respect to the intermediate carriage. With the prior push-pull cables, if the cable extended over a long run, kinking of the cable became a problem and if the cable extended over either a short run or long run, an excessive amount of force would be required to transmit motion from the actuator to the operating unit.